C5. Natural and Quasi-experiments Flashcards
Why do we look at “natural” or “quasi experiements”?
Randomisation can ensure independence and eliminate selection bias, but some experiments would be highly unethical.
Sometimes nature or some other outside agency steps in and does what an ethics committee would never allow.
Examples of natural experiments?
Tornado passing through a community, or a landslip in a Brazilian favela.
How are natural experiements valid?
Nature randomly (ind. of potential outcomes) allocates people treatment or non-treatment.
Some people then behave differently or find themselves in differnet circumstances.
Social scientists can compare outcomes knowing that selection bias is not a significant factor.
How are quasi-experiements valid?
Institutional arrangements can sometimes play a similar role of dividing people into the treatment and control group in a way which is independent of potential outcomes.
